PHOTOREFRACTIVE AND PHOTOCONDUCTIVE FEATURES OF THE NANOSTRUCTURED MATERIALS

Photoconductive and photorefractive characteristics of fullerene- and nanotubes-doped organic thin films based on conjugated organics, such as polyimide, polyaniline, pyridine, etc. have been studied. In addition, the liquid crystal mesophase with nanoobjects has been investigated. The increase of the charge carrier mobility of nanosensitized organics has been established. The nonlinear refraction and cubic nonlinearity have been investigated at wavelength of 532 nm via four-wave mixing technique using Raman-Nath diffraction regime. The thin holographic grating has been written at the spatial frequencies placed in the range of 90-150 mm-1. The energy density has been chosen in the range of 0.1-0.9 J × cm -2. The correlation between photoconductive and nonlinear optical parameters has been revealed. The nanostructured materials can be proposed for different area of nano- and microelectronic applications.

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Cubic Nonlinearity of Molybdenum Disulfide Nanoflakes

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.17594 ◽

2020 ◽

Vol 20 (7) ◽

pp. 4373-4375

Author(s):

Tikaram Neupane ◽

Quinton Rice ◽

Sungsoo Jung ◽

Bagher Tabibi ◽

Felix Jaetae Seo

Keyword(s):

Molybdenum Disulfide ◽

Nonlinear Absorption ◽

Repetition Rate ◽

Nonlinear Refraction ◽

Optical Nonlinearity ◽

Excitation Intensity ◽

Resonant Excitation ◽

Excitation Source ◽

Cubic Nonlinearity ◽

532 Nm

The cubic optical nonlinearity of molybdenum disulfide (MoS2) nanoflakes was characterized by Z-scan and I-scan with resonant excitation. The excitation source was a ~6 ns laser at 532 nm with a 10 Hz repetition rate. The open and closed Z-scan analyzed the nonlinear absorption and nonlinear refraction properties of MoS2 nanoflakes. The I-scan technique characterized the nonlinear transmittance properties of MoS2 nanoflakes at the peak and valley of closed Z-scan trace as a function of excitation intensity.

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Exfoliated Bi2Te3 nanoparticle suspensions and films: morphological and nonlinear optical characterization

Nanophotonics ◽

10.1515/nanoph-2021-0335 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Rashid A. Ganeev ◽

V. S. Popov ◽

A. I. Zvyagin ◽

N. A. Lavrentyev ◽

A. E. Mirofyanchenko ◽

...

Keyword(s):

Thin Films ◽

Nonlinear Optical ◽

Nonlinear Refraction ◽

Colloidal Suspensions ◽

Saturable Absorption ◽

Reverse Saturable Absorption ◽

Optical Parameters ◽

Probe Radiation ◽

Saturation Intensity ◽

532 Nm

Abstract Bismuth telluride nanoparticles (NPs) attract attention due to the growth of sensitivity of the Bi2Te3 NPs-containing registrars in the near- and mid-infrared ranges. We describe the synthesis and characterization of these structures and analyze the low-order nonlinear optical properties of the colloidal suspensions and thin films containing Bi2Te3 NPs using 1064 and 532 nm, 10 ns pulses. Colloidal Bi2Te3 NPs demonstrate saturable absorption and positive nonlinear refraction (saturation intensity 7 × 108 W cm−2, nonlinear absorption coefficient β SA = −7 × 10−8 cm W−1, nonlinear refractive index γ = 9 × 10−12 cm2 W−1), while at stronger excitation by 532 nm, 10 ns pulses the reverse saturable absorption dominates over other nonlinear optical processes. We achieved significant growth of the nonlinear optical parameters of the thin films containing these NPs (film thickness l = 60 nm, β SA = −1.2 × 10−4 cm W−1, γ = 5 × 10−7 cm2 W−1 in the case of 532 nm probe radiation and β = −5 × 10−5 cm W−1, γ = 6 × 10−8 cm2 W−1 in the case of 1064 nm probe radiation) compared with colloidal Bi2Te3 NPs and discuss the observed peculiarities of the nonlinear response of Bi2Te3 nanostructures.

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Organic thin films with charge-carrier mobility exceeding that of single crystals

Journal of Materials Chemistry C ◽

10.1039/c7tc03324a ◽

2017 ◽

Vol 5 (39) ◽

pp. 10313-10319 ◽

Cited By ~ 8

Author(s):

Zachary A. Lamport ◽

Ruipeng Li ◽

Chao Wang ◽

William Mitchell ◽

David Sparrowe ◽

...

Keyword(s):

Crystal Structure ◽

Thin Films ◽

Charge Carrier ◽

Single Crystal ◽

Single Crystals ◽

Carrier Mobility ◽

High Mobility ◽

Organic Thin Films ◽

Charge Carrier Mobility

Through processing, spin-cast OTFTs outperform single-crystal OFETs by making accessible the high-mobility direction in the same crystal structure.

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The Influence of Nitrogen Position on Charge Carrier Mobility in Enantiopure Aza[6]helicene Crystals

10.26434/chemrxiv.7458719.v1 ◽

2018 ◽

Author(s):

Francesco Salerno ◽

Beth Rice ◽

Julia Schmidt ◽

Matthew J. Fuchter ◽

Jenny Nelson ◽

...

Keyword(s):

Solid State ◽

Charge Carrier ◽

Carrier Mobility ◽

Chemical Structure ◽

Crystal Packing ◽

Charge Carrier Mobility ◽

Individual Factor ◽

Charge Mobility ◽

Order Of Magnitude ◽

Small Change

<p>The properties of an organic semiconductor are dependent on both the chemical structure of the molecule involved, and how it is arranged in the solid-state. It is challenging to extract the influence of each individual factor, as small changes in the molecular structure often dramatically change the crystal packing and hence solid-state structure. Here, we use calculations to explore the influence of the nitrogen position on the charge mobility of a chiral organic molecule when the crystal packing is kept constant. The transfer integrals for a series of enantiopure aza[6]helicene crystals sharing the same packing were analysed in order to identify the best supramolecular motifs to promote charge carrier mobility. The regioisomers considered differ only in the positioning of the nitrogen atom in the aromatic scaffold. The simulations showed that even this small change in the chemical structure has a strong effect on the charge transport in the crystal, leading to differences in charge mobility of up to one order of magnitude. Some aza[6]helicene isomers that were packed interlocked with each other showed high HOMO-HOMO integrals (up to 70 meV), whilst molecules arranged with translational symmetry generally afforded the highest LUMO-LUMO integrals (40 - 70 meV). As many of the results are not intuitively obvious, a computational approach provides additional insight into the design of new semiconducting organic materials.</p>

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Enhanced Photocurrent Response Speed in Charge-Density-Wave Phase of TiSe2-Metal Junctions

Nanoscale ◽

10.1039/d1nr01810h ◽

2021 ◽

Author(s):

Thayer Walmsley ◽

Yaqiong Xu

Keyword(s):

Carrier Mobility ◽

Density Wave ◽

Transition Metal Dichalcogenides ◽

Response Speed ◽

Charge Carrier Mobility ◽

Metal Dichalcogenides ◽

Charge Density Wave Phase ◽

Large Sheet ◽

High Charge Carrier Mobility ◽

Significant Attention

Group IVB transition metal dichalcogenides (TMDCs) have attracted significant attention due to their predicted high charge carrier mobility, large sheet current density, and enhanced thermoelectric power. Here, we investigate the...

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